Excavator tooth



y 1961 F. D. STEPHENSON 2,982,035

EXCAVATOR TOOTH Filed April 28, 1958 2 Sheets-Sheet 1 INVENTOR.

FERRALD DAN/H. STEPHENSON BY I AT TOPNEVS mom tsfi P EXCAVATOR TOOTH Ferrald Daniel Stephenson, 4562 Lamina, Lakewood, Calif., assignor of ten percent to Thomas C. Whisler, Sn, Alameda, Calif.

Filed Apr. 28, 1958, Ser. No. 731,215

11 Claims. '(Cl. 37-142 customary to provide removable and replaceable teeth or tips for the teeth which can readily be detached in the field when wornand can as readily be replaced with new members. In someinstances the replaceable parts are supported directly on the dipper bucket or other excavating devise referred to-as a base, while in other instances the replaceable parts are supported directly upon an 7 adapter which in turn is supported upon the base. 'In

either instance, there exists a problem of providing a firm immovable support for the replaceable member;

when it is in operating condition and also of afifording a construction so that the part can readily be removed when worn and as readily replaced with only ordinary field tools and field labor.

In use theforces which are-exerted upon the tooth tip and through the tooth tip onto adapted or directly onto the base are of complex nature being imposed from various directions at different times during the digging operation. Various forces at various directions are also imposed depending upon the nature of the material being excavated. For discussion it can be considered that the base is moving in a horizontal direction and that the leading edge is moving from right to'left and further, that'- the adapter (if used) and the tooth tip are arranged so that they project forwardly from the leading edge and are contoured so as to be principally disposed in the direction of advance of the edge. -If then the tooth tip encounters resistance directly ahead, theresulting force on the tooth tip and ultimately the base is approximately in the general line of'the structureand is well resisted. It is'usual to provide all-shaped inter-engagement between the tooth tip andthe adapter or base so that a resulting force in'the' indicated direction tends to wedge the tooth tip even more tightly upon its supporting struc? ture. Thisiis for the reason that-the point or apex of the ,V is directed forwardly. This arrangement providesfor.

. easy assembly and disassembly and generally issatisfactory so long as thGyl'llfljOl'llY of the forces aretiinpose'd .in theindicated directionr l F In muchexcavation, -however, thetooth .tip is moved in a'direction having amajor component transversely o the near .thegextr'emitymf 'thewtootlzt tip. This imposes-a largedransverse downward force}; (Figures Sand 9 upon the. tooth tip. 1 If jthisi vertioallyidownward :force,

so direction first-. discussed. That is,f.the point-;ofthe tooth tip is liftedyoften with the m'axinium load being imposed q is posed sotliatangarbitrarycenterlinefihasahorizontal enemas nf'arid"servesalsoto loeate ,ahoiizontal Mi l e tip from its base. Considered in another'way, the component 4 of the force parallel to or along the upper surface of the V is a force having a moment arm about an arbitrary central point P (Figure 8) within the base so that there is a tendency under these conditions to rotate (counterclockwise in Figure 8) or bend the tooth tip ofi of its support, a tendency which if productive of motion is often referred to as creeping. In practice, if creeping once starts and produces some Wear it is rapidly progressive and the tooth tip becomes unsatisfactorily loose and quickly is useless.

It is therefore an object of the invention to provide an excavator tooth having a removable tip so related to its base as to resist satisfactorily not only the head-on forces but also the transverse or downward forces which otherwise tend to produce creeping.

Another object of the invention is to provide an excavator tooth having an improved inter-connection between the removable tooth and its supporting base.

A still further object of the invention is to provide.

An 'additionalobjectof the invention is to provide an excavator tooth whichis readily installed and, once installed, is firmly mounted so as to resist loosening and wear-producing motion throughout its operational life. A still further object of the invention is in general to improve excavator teeth.

Other objects, together with the foregoing, are attained in the embodiment of the invention described in the ac-. companying description and illustrated in the accompanying drawings in which: Figure 1 is a side elevation with broken away portions in cross section on a vertical longitudinal plane showing the excavator tooth in initial assembly position with respect to an adapter and base mounting;

Figure 2 is a view similar to Figure l but showing the. 7

parts in a partially assembled condition;

Figure 3 is a similar view, but showing the partsin fully assembled and operatingcondition;.

Figure 4 is a plan, certain portions being broken away,

of an excavator tooth on its base;

Figure 5 is a cross section the plane of which is indicated by the line5--5 of Figure 3; V p

Figured is a 'view like Figure -5 and showing a cross section the plane of which is indicated by the line 6 6 Figure 7 is a perspective view of a mounting.

Figures and9 are diagrams illustrative ofo ne of the" forcesimposed upon the structure and its resolution into components.

While the excavator'tooth of the inventioncan be, and has been successfully incorporatedin a number of variant forms it has, been cornmerciali zed in the form shown} herein. In,,.thisenvironment,there is provided aQbase including a dipper body 6 towhich a removable adapter 7 has been" applied. It is understood that in sem n. stances the body 6 and the adapter 7 are separate entities p whereas" inother instances the body 6 and the adapterl'l are. integral. f In both instances they coust t lfi -l 15; ither instanceit is consid fi 29 ofiidiscnssi'on. that the s sliding member 7 Patented May 2, 196i of" symmetry. The base 7 includes an upper central surface 9 substantiallyplanar and converging forwardly or toward the left in the figures in the direction of the centralplane .8. Similarly and symmetrically arranged. is a lower planar central surface 11 also converging to- Ward the central plane .8. a a a At both sides of the structure, as shown in Figure 4, there are provided parallel upper surfaces 12 and 13 which are usually disposed at the extremities of lateral ribs 14 and 15. The surfaces .9, 12 and 13 near their ends curve toward the outer surface 16 at the top of the member 7. There are similar ribs 17 and 18 having surfaces 19 and 20 substantially parallel with the surface 11 and at their ends curving toward the nether surface 21 of the member 7. The surfaces 9 and 11 are dihedral surfaces for the most part defining a V -shaped inter-connection on the base 7. Thesurfaces 12, 13, 19 and 20 are other dihedral, planar converging surfaces also partially defining the V-shaped inter-connection on the base 7.

Adapted to be assembled with the base 7 is a tooth tip 22 being substantially rectangular in plan and having an upper surface 23 and a lower surface 24. These surfaces are substantially planar, are usually although not necessarily approximately parallel to the respective surfaces 9 and 11, and converge into a relatively sharp, linear point 25 at the leading edge of the tooth tip.

The interior 'of the tooth tip 22 is provided centrally with a surface26 which is. substantially planar and extends between lateral surfaces 27 and 28 which are ap proximately parallel thereto; the arrangement being such that when the tooth tip is assembled on the base the surfaces 27 and 28 substantially abut the surfaces 12 and 13, whereas the surface 26 may abut or may have some clearance with respect to the subjacent surface 9.

Since preferably the parts are substantially symmetrical about the center plane 8, the tooth tip 22 likewise has a central surface 31 adapted to be disposed opposite, and perhaps in abutment with the nether surface 11 and also has a pair of approximately parallel side surfaces 32 and 33 which preferably contact in assembled condition the adjacent lower surfaces 19 and 20 of the body 7. While the various convergent surfaces forming the V inter-connection are for the most part in abutment, there is some variation possible in commercial practices and techniques so that not all of the surfaces need be in forced engagement in actual operation. If several of the surfaces are in reasonable abutment that is commercially satisfactory.

The tooth tip 22 thus is not only in firm engagement with the base 7 above and below, but also especially for heavy-duty installations, is. provided with side walls 41 and 42 having outer planar faces .43 and44 andalso having interior surfaces 46 and. 47 which are approxi- 'mately parallel to and, often,.in assembled condition abut firmly held under pressure because of the presence of the resilient rubber, yet when the wedge is driven out, the parts can easily be detached.

As so far described, the excavator tooth is typical of a relatively standard construction. Pursuant to the invention, the base 7 is not entirely symmetrical. In the leading portion of the base, whereas the surface 11 is continued directly-to merge with the blunt forward surface 71, the upper surface 9 is not continued to converge symmetrically toward the forward surface 71. Rather, at a convenient point in its length, the surface 9 no longer converges. At a zone of inflection 72, the convergence of the surface 9 stops. At that zone there arises a new upper surface 73. This is central and planar like the surface 9 but instead of converging further toward the central plane 8, diverges forwardly and upwardly therefrom and from the plane 3, finally merging with the forward surface 71 at a point considerably higher or farther from the center than the zone 72. The planar surface 73 may or may not be parallel with the surface 11 and may or may not diverge upwardly from the inflection zone 72 at the same degree or rate as the surface 9 diverges therefrom in the opposite direction.

The important factor is that the upper surface 73 and the raised surface 71 afford an upstanding discontinuity or toe 74 characterized by arr-upstanding projection in the leading, upper portion of the base 7. The toe 74 is partly bounded by the surface 73 which is different in inclination, or is inclined in an opposite sense to the inclination of the surface 9. There is a greater thickness of metal beneath the surface 73 than there would be if the surface 9 were continued to the end of the base, as is usual. In this sense, there is a greater thickness of metal, as the surface 71 is approached, than there would be if the surface 9 continued to the surface 71.

While the present drawings are roughly to scale with present commercial embodiments, the precise angles illustrated are not essential or critical. The effect of the surface 73 can, however, be understood by again considering a vertically downward force 2 (Figure 9) resisted at the surface 73. If-this vertically downward force is analyzed into its two components, as previously was done, one of the components 5 is parallel to the plane of the surface 73. The other component 1 is normal to the surface 73. While the normal component 1 has no effect other than to press the parts together, the component 5 parallel to the surface 73 has a direction tending to force the tooth tip 22 farther onto the base 7 or to drive the various inclined wedge surfaces more firmly into contact. As before, if the force 5 parallel to the surface 73 is considered as a force having a moment arm about some central point P in the toe 74, then the resulting rotational force (clockwise in Figure 9) is opposite to the ,dislodging or downward force and tends to oppose thefcreeping action originally defined. Thus by the pro.- vision of the upwardly extending toe 74, a substantially improved inter-connection between the tooth tip and the tion in order that forces from lateral and vertical directions can be resisted. t v I 'In order to hold the tooth tip firmly upon but readily removable from the base, the tooth tip itself is provided with apair of central aligned openings Sland 52 which are designed. to be in approximate registry with/a central, vertical aperture E l-extending through the base. 7.

wear ring 58 embedded' therein. except. for itsexposure alongfthe' leading portion of the wedge, so that the ring can beseated in a corresponding depression-59 in the th'eap'erture'fil .wheh the wedge is tightly en and. eventually rounds-into aforwardsurface 79 approxi- 'mately parallel to the surface 71. The surface l78in part defines a forward portion of the hollow interior of the tooth tip. This forward portion is an enlargement I as" compared to-the immediately adjacent part of the hollow'interior, especially that portion thereof between the forward partsof the surfaces 26 and 31. The sura S1V G HbUtITI IFHL WhQI1 ike parts are appropriately ,assema bled .and particularly under the, forces, exerted during i transverse centralplaneand includi ;.Since it is" desired that the tooth tip 21 be reversed-to increase its effective life after initial wear, the, surface 31 also has a zone or line of inflection 81 which marks the beginning of a divergent planar surface 82 rounding at its forward portion into the surface 79. The surface 82, like the surface 78, partially defines an enlargement in the hollow interior of the tooth tip as compared to the relatively small volume defined between the forward portion of the surfaces 26 and 31. With this arrangement, when the wedge'56 has been removed and the tooth tip 22 driven forwardly and olf of its base, the tooth tip can be rotated or inverted and repositioned. The surface 82 ,is then in tight abutment with the surface 73 and the wedge can then be reinstalled. In the inverted position the toothv tip is again supported by the toe 74 against the downwardly exerted. dislodging forces and thecreeping is also resisted.

In the assembly of the tooth tip onto the base 7 the parts move progressively substantially as shown in Figures l, 2 and 3, the precise direction of motion of the tooth tip onto the basein the initial part of the assembly being immaterial. The motion is generally along the line of symmetry .8 whereas in the final part of the assembly there is usually, although not necessarily, a relative sliding movement of thesurfaces 73 and 78 until the parts are in home position as illustrated in Figure 3. The particular angularities involved in the various surfaces and the clearances which are provided between some of them may change during manufacture (casting) and after use. They may be varied to accommodate manufacturing practices or particular requirements of an individual installation, but the general proportions and arrangements and angularities of the parts are conveniently made approximately as illustrated in the drawings.

If this arrangement is followed there is provided a removable excavator tooth which is firmly mounted when in position and which has especial resistance to forces tending to produce a creeping or rotary dislodgement of the tooth tip. The device is readily fabricated by the usual casting methods and is reversible as desired. It is easily assembled bythe usual techniques and withv the usual field tools and isas readily disassembled either forreversal or for replacement.

What is claimed is: 4 i

1, An excavator tooth comprising a base having a forward portion symmetrical about a horizontal plane and defined by side surfaces and by upper and lower planar merging with a base surface substantially normal to said horizontal plane. d

2. An excavator tooth comprising a base having a central plane of symmetry and partially defined by upper and lower planar central surfaces converging toward said plane of symmetry in .a forward direction, a toe merg- "ing with and upstanding from one of said base central surfacesrand having a' planar face diverging from said base plane of symmetry in=a forward direction, a tooth v tip having a central plane of symmetry and partially defined by, interiorcupper and lower planar central surfaces 7 converging toward said plane of symmetr'y in a forward direction, said :tip also having van interior planar' face merging with and extending from one of said tip central.

' surfaces and diverging from said tip plane of symmetry in a forwardzdirection,;and means for holding said; base,

and said tooth. tip in engagement with said icentralsur- ,faces'substantially"in engagemenfand-with only said'di- 1 verging "planar face fofsaidtoe in abutmentwith said interiorplanar face ofsaidtooth tip;

, ;3.l-Ari 'e'xcavatorftooth comprising],

a base 'a' fsubstantiallyparah lel planar'side surfaces, including a planar lower surface;

face, and a tooth tip adapted to be assembled with said.

base and when so assembled including substantially parallel planar side'walls substantially contacting said side surfaces, including a planar lower wall substantially contacting said lower surface, including a planar upper wall substantially contacting said upper surface, and including means defining a lower surface substantially contacting said top surfaceof said toe.

4. An excavator tooth comprising a base having a transverse central plane and including side surfaces, including upper and lower planar surfaces converging forwardly toward said plane, and including a toe upstanding from said upper surface in the forward portion thereof and in part defined by a planar top surface diverging forwardly away from said plane, and a tooth tip adapted to be assembled with said base and when so assembled including side walls substantially in abutment with said side surfaces, including planar upper and lower walls substantially in abutment with said upper and lower surfaces, and including an interior lower wall substantially iii abutment withsaid top surface.

5. An excavator tooth base having a transverse central plane, said tooth base including side surfaces, including upper and lower planar surfaces convergingforwardly toward said central plane, said tooth base terminating in a leading portion and having a toe upstanding farther and farther from said central plane at positions closer and closer to said leading edge and in part defined by a top load receiving surface approximately parallel to said lower surface.

6. An excavator tooth comprising an interfitting base and tooth tip, said base having a transverse central plane of symmetry and including side surfaces and including upper and lower planar surfaces converging forwardly toward a leading edge, said tooth tip including side walls in substantial abutment with said side surfaces, including upper and lower walls in substantial abutment with said upper and lower surfaces respectively, and interfitting means on said baseand on said tooth tip defining abutting planar'areas merging with said upper planar surface and said upper wall and diverging from said central plane in'a direction to impose a force component in said' plane and in a direction urging said tooth tip into tighter abutment with said base when a downward force normal to said plane islexerted on said tooth tip.

7. An excavator tooth base comprising a wedge-shaped member having substantially parallel side surfaces and having planar upper and lower surfaces converging forwardly toward a transverse plane of symmetry, said tooth base terminating in a leading portion, and means forming a toe upstanding from said member adjacent said leading portion, said toe having a planar top area which is the only area of said tooth base diverging forwardly away from said plane of symmetry.

8. An excavator tooth tip comprising a hollow wedgeshapedmember having, substantially parallel side walls and having upper and lower walls converging forwardly .toward a transverse plane of symmetry, all of said walls defining a wedge-shaped cavity terminating at a forward "relatively thin leading edge,"a projection. on said base and having a surface mergingwithone face of said wedge, a said projectionbeingthickestat its extreme leading por- ,tion relative to 'said plane of symmetry, a tooth ftip having four walls defining a V-shaped wedge hollow interior adapted to overlie said base and having a wall diverg ing forwardly from said plane of symmetry and overlying said projection, and means for holding "said tooth tip on said base with said V-shaped wedge portions substantially in abutment and with said surface and said wall in abutment.

10. An excavator tooth comprising a wedge-shaped base having a transverse central plane of symmetry'and including upper, lower and two side surfaces and a tooth tip having a wedge-shaped cavity adapted to envelop said base and abut said upper, lower and two side surfaces, and means including abutting planar portions on said base and on said tooth tip inclined relative to said central plane in a direction opposite to the direction of inclination of the upper surface of said wedge-shaped base relative to said central plane for imposing a force component urging said tooth tip into tighter abutment with said base when a downward force is exerted on said tooth tip.

11. An excavator tooth comprising a base having a transverse plane of symmetry and having the contour of a V-shaped wedge defined between an upper plane and a lower plane converging forwardly toward said plane of symmetry except for a central projection upstanding from said wedge above said upper plane, said projection having an upper planar surface that is increasingly farther from said plane of symmetry when measured at increasingly forward positions, and a'hollow tooth tip movable into assembled position with said base, the hollow in said tip having substantially the contour of said V-shaped wedge and having an interior surface substantially abutting said upper planar surface of said projection in said assembled position.

References Cited in the file of this patent UNITED STATES PATENTS 

